1. Field of the Invention
The present invention generally relates to methods and structures for protecting the occupants of a military vehicle. More particularly the invention relates to structures for mitigating the effect on vehicle occupants of an upward force on a vehicle created by an explosive blast underneath the vehicle. The device is intended for use on vehicles travelling in combat areas where land mines, improvised explosive devices (IEDs) or like munitions explode as a vehicle passes over them. The invention is also related to military vehicle “V hulls” whose underside has a V shape or a truncated V shape; the present invention is particularly suitable for such vehicles. V hulls deflect blast forces occurring under a vehicle to a generally outboard direction from the vehicle. The invention uses a vane that cooperates with the V hull to provide an additional deflection of blast force, so that the blast force ultimately exerts a downward force component on a vehicle. The invention thus mitigates the vertical rise or “hop” of the vehicle when a mine explodes beneath it. The mitigating effect of the invention reduces spinal injuries or other injuries to occupants of the vehicle.
2. Background Art
A relevant technology has to do with blast fences or jet blast deflectors commonly used at airports. These devices are wall-like structures positioned behind jet aircraft so that jet exhaust is directed upward and away from nearby personnel, equipment or buildings. Jet blast deflectors are described in numerous places, an example being http://en.wikipedia.arg/wiki/Jet_blast_deflector. A jet blast deflector is also shown by U.S. Pat. No. 7,437,987 B1 to Ohnstad et al. Another relevant technology is gun muzzle design wherein the muzzle has vents on the upper side. When the gun fires, part of the effluent from the gun blast is directed upward by the vents so as to create a downward force counteracting rise of the gun barrel. An example of the aforementioned gun muzzle technology is U.S. Pat. No. 8,087,337 to Cary. The web site http://www.brownells.com/.aspx/pid=27642/Product/S-W-M-P-PRE-FIT-MATCH-GRADE-BARRELS shows anti rise gun muzzles as well.
Still another relevant technology has to do with spoilers, air dams or wings fitted to automobiles. Air dams are used on the front of vehicles to reduce air flow under the vehicle as it travels, thereby reducing drag. Spoilers on the aft ends of vehicles typically increase air pressure at the zone behind the rear window over the trunk to create down force at that zone. Other so-called spoilers are actually wings that create down force on vehicles in the way aircraft wings create lift. A general discussion of vehicle air dams, spoilers and wings is at http://en.wikipedia.org/wiki/Spoiler (automotive). Relevant art is also shown by a floor sweeper vehicle having a flap to upwardly deflect a stream of air and debris into a hopper, as shown in U.S. Pat. No. 6,154,922 to Vanderlinden.
Of possible relevance is U.S. Patent Application Publication 2011/014817 A1 to Tunis et al. The main thrust of Tunis is a structural through-channel open at the top and bottom of a vehicle body to allow blast force under the vehicle to escape to a zone above the vehicle. Such a channel is shown in FIGS. 1 and 2 of Tunis. Additionally, at FIGS. 25 through 28 of Tunis are notional diagrams of blast force vectors, as at 974. These vectors are affected by a V hull of proposed vehicle 970 and proposed hull structural channels. FIGS. 26 and 27 show a vehicle hull incorporating elbow-shaped structural channels 980. Tunis asserts that force vectors 974 directed along a V hull surface into channels 980 cause a net downward force on vehicle 970. But vector 974 in FIG. 26 is parallel to the lower half of channel 980; this vector would impact the outboard wall in the upper half of the channel 980. The impact is in an upward direction, so the kinetic energy of effluent travelling along vector 974 imparts an upward force component on channel 980. Also, a detonation at a location on the ground will have force vectors radiating from the location. Some of the radiating vectors will impact the underside (or outboard side) of the lower half of channel 980. The impact will cause an upward force component on vehicle 970. Tunis does not reveal how the foregoing impacts are overcome so as to result in a net downward force component caused by structural channels 970; in fact, it appears that the aforementioned impacts cause a net upward force on vehicle 970.